【设计模式】3.装饰模式

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https://blog.csdn.net/weixin_39190382?type=blog

0. 前言

装饰模式

1. 第一版

class Person:
    def __init__(self, name):
        self.name = name
    
    def wear_t_shirts(self):
        print("大T恤 ", end="")
    
    def wear_big_trouser(self):
        print("垮掉 ", end="")
    
    def wear_sneakers(self):
        print("破球鞋 ", end="")
    
    def wear_suit(self):
        print("西装 ", end="")
    
    def wear_tie(self):
        print("领带 ", end="")
    
    def wear_leather_shoes(self):
        print("皮鞋 ", end="")
    
    def show(self):
        print(f"装扮的{self.name}")


# 客户端代码
if __name__ == "__main__":
    xc = Person("小菜")
    print("\n第一种装扮: ")
    xc.wear_t_shirts()
    xc.wear_big_trouser()
    xc.wear_sneakers()
    xc.show()
    
    print("\n第二种装扮: ")
    xc.wear_suit()
    xc.wear_tie()
    xc.wear_leather_shoes()
    xc.show()
    
    input()  # 相当于C#的Console.Read()

增加"超人"类，需要修改Person,违反了开放-封闭原则

2. 第二版

from abc import ABC, abstractmethod

# Person 类
class Person:
    def __init__(self, name):
        self.name = name
    
    def show(self):
        print(f"装扮的{self.name}")

# 服饰抽象类
class Finery(ABC):
    @abstractmethod
    def show(self):
        pass

# 具体服饰类
class TShirts(Finery):
    def show(self):
        print("大T恤 ", end="")

class BigTrouser(Finery):
    def show(self):
        print("垮裤 ", end="")

class Sneakers(Finery):
    def show(self):
        print("破球鞋 ", end="")

class Suit(Finery):
    def show(self):
        print("西装 ", end="")

class Tie(Finery):
    def show(self):
        print("领带 ", end="")

class LeatherShoes(Finery):
    def show(self):
        print("皮鞋 ", end="")

# 客户端代码
if __name__ == "__main__":
    xc = Person("小菜")
    
    print("\n第一种装扮:")
    dtx = TShirts()
    kk = BigTrouser()
    pgx = Sneakers()
    
    dtx.show()
    kk.show()
    pgx.show()
    xc.show()
    
    print("\n第二种装扮:")
    xz = Suit()
    ld = Tie()
    px = LeatherShoes()
    
    xz.show()
    ld.show()
    px.show()
    xc.show()

建造者模式过程必须稳定，而这里建造过程不稳定，可以先传西装，外套，也可以反过来。

3. 第三版

装饰模式

from abc import ABC, abstractmethod

# Person类 (ConcreteComponent)
class Person:
    def __init__(self, name):
        self.name = name
    
    def show(self):
        print(f"装扮的{self.name}")

# 服饰抽象类 (Decorator)
class Finery(Person):
    def __init__(self):
        self._component = None
    
    # 打扮/装饰方法
    def decorate(self, component):
        self._component = component
    
    def show(self):
        if self._component:
            self._component.show()

# 具体服饰类 (ConcreteDecorator)
class TShirts(Finery):
    def show(self):
        print("大T恤 ", end="")
        super().show()

class BigTrouser(Finery):
    def show(self):
        print("垮裤 ", end="")
        super().show()

class Sneakers(Finery):
    def show(self):
        print("破球鞋 ", end="")
        super().show()

class Suit(Finery):
    def show(self):
        print("西装 ", end="")
        super().show()

class Tie(Finery):
    def show(self):
        print("领带 ", end="")
        super().show()

class LeatherShoes(Finery):
    def show(self):
        print("皮鞋 ", end="")
        super().show()

# 客户端代码
if __name__ == "__main__":
    xc = Person("小菜")
    
    print("\n第一种装扮:")
    pqx = Sneakers()
    kk = BigTrouser()
    dtx = TShirts()
    
    pqx.decorate(xc)    # 装饰过程
    kk.decorate(pqx)
    dtx.decorate(kk)
    dtx.show()
    
    print("\n第二种装扮:")
    px = LeatherShoes()
    ld = Tie()
    xz = Suit()
    
    px.decorate(xc)     # 装饰过程
    ld.decorate(px)
    xz.decorate(ld)
    xz.show()
    
    input()  # 相当于C#的Console.Read()